Process of clarifying and decolorizing oils



' UNITED STATES PATENT OFFICE.

RUSSELL WILLIAM MUMFORD, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGN- MENTS, TO DARCO CORPORATION, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

PROCESS OF CLARIFYING AND DEGOLORIZING OILS..

No Drawing.

To all whom it may concern:

Be it known that I, RUSSELL WILLIAM MUMronD, a citizen of the United States, residing at New York, in thec ounty of New York and State of New York, have invented certain new and useful Improvements in Processes of Clarifying and Decolorizing Oils, of which the following is a specification.

This invention relates to processes of clarifying and decolorizing oils; and it comprises a method of bleaching fatty oils, such as cotton seed oil, which is also applicable to mineral oils, wherein such an oil is agitated for a time in contact with a particular type of decolorizing carbon obtained by a slow carbomzation of vegetable matter in such manner as to leavean open-textured granular material having a porous structure representing approximately the original cellular structure of the material carbonized, the oil and carbon being afterward separated; the contact of oil and carbon being accompanied, or not, as the case may be, with exposure to the action of an electric current; all as more fully hereinafter set forth and as claimed.

Other things being equal, the commercial value of a vegetable oil, such as cotton seed oil, cocoanut oil, linseed oil, etc., depends mainly upon its lightness of color and upon its clarity; its transparency or brightness. The latter quality, however, is particularly difficult .to secure with most of the methods of refining now in use. To be absolutely bright or clear, an oil must not only be free of insoluble matter or dirt in particles of sensible size, but also of the very much finer particles of the character of those occurring in colloidal suspensions. Particles of this latter order of fineness are very difficult indeed to remove from oils by ordinary purifying means. They cannot be filtered out and their collection in coagula of various kinds is difficult and uncertain. In the case of the thick oils used for varnish it is indeed a common practice after all other purifying means have been resorted to, to allow the oils to stand undisturbed for long periods of time, sometimes months and years, in order to allow these very fine particles to settle. Almost equal difficulty occurs in the production of light colored oils from dark colored oils. It is very hard Specification of Letters Patent.

lubricating oil, kerosene, etc.

Patented May 3, 1921.

Application filed July 11, 1917. Serial No. 179,930.

to remove dissolved color-giving substances from fatty oils and bleaching, although often resorted to, is very frequently merely a transitory thing, most bleachings being due to oxidation or reduction and the effect being often not permanent. The use of drastic chemical treatments in the case of' most fatty oils is of course precluded. About the same considerations apply to the treatment of mineral oils. The most common decolorizing and clarifying agent used with these oils is fullers earth or some similar type of hydrated clayey porous material. Fullers earth decolorizes very well and also has a clarifying effect but neither effect is as extensive as can be desired; and in the case of edible oils the action of fullers earth is, further, attended'byanundesirable effect in that it usually leaves the oil with vapid or insipid taste. The use of chemical bleaching agents is also detrimental with edible oils for much the same reason; they impair the taste.

The object of the present invention is to provide a cheap, simple and ready method of refining these oils wherein I can both lighten the color to a high extent and can" particularly as applicable to vegetable oils,-

such as cotton seed oil, I wish it to be understood that it may also be used with oils of any other origin, such as mineral oils, This method consists in substance in the use of a particular decolorizing carbon, which I may hereinafter call my decolorant, produced by charring various vegetable matters in such a manner as to leave a porous, open textured granular material; the porousstructure representing approximately the original cellular tissue of the vegetable material charred. .Such a carbon when used with a fatty or mineral oil, as I have dc-- scribed, not only removes color from the oil to an unusual extent but also has the power of flocculating or attracting suspended or undissolved materials; even those'particles which are in a state of what may be called quasi-solution or suspension.

This decolorant I produce bya special method of charring vegetable matters, such colloid material, like starch, in the event that such, Vegetable, material does not already contain a suflicient amount of colloid materials. The vegetable material in a granulated form is then mixed with grains of a material such as dolomite, adapted to act as a spacing agent and also to evolve carbon dioxid or other purifying gas continuously throughout a wide temperature range. The mixture is then slowly heated in a vented retort. Under the action of the heat, the moisture is first expelled, taking with it various volatile matters and puffing up the vegetable material and rendering it porous. Then the material chars slightly, giving off various vapors and gases; Because of the presence of the mineral spacing agent, these vapors and gases are afforded an opportunity to escape without in their turn undergoing decomposition in the presence of the grained vegetable matters. As the charring goes on the dolomite begins to evolve carbon dioxid at a temperature somewhere around 250 C. This carbon dioxid is taken up in the pores of the charring mass and as the temperature goes up, it exercises a beneficial action on these pores, probably by opening them up. The temperature is then carried to a high point and the'material is dumped into water and washed. -Theultimate material' is .a

- granular carbon-having open pores representing, more or less closely, the cellular structure of the original material before carbonization. It is vastly more open-tex tured than charcoal in which, in the usual methods of making charcoal, the pores are closed and sealed by the deposition of carbon in them. When wood is first charred in making charcoal, the vapors and gases accumulate in the pores where they are in turn carbonized, depositing carbon and closing the pores. charcoal where a hard, dense product is wanted. In the present material, the effort is to have open pores.

This material unites a number of ties. It has a large surface area of of carbon which is very active in adsorbing or removing coloring matters from solution being unusually active in this way.

In addition, this material has the property possessed by kieselguhr and some other highly. porous mineral matters,'of collecting or flocculating suspended solids. .In other words, this particular material'unites the property of decolorizing with that of 1'en1ovmg suspended solids.

In,applying the peculiar properties of this material in the present process, it is merely proper- Thisis desirale in making I a form five minutes.

necessary to mix the oil, which may be any crude or refined oil, with 2 to 10 per cent. of the decolorant and agitate energetically for a time; finally separating the decolorant from the oil by any suitable'means such as filter pressing. Agitation may be by an air blast,a stirrer or any other suitable means. I find it best to work with the oil at about LOO-110 C. I do not permit the oil, however, actually to boil. This high temperature both promotes the action here desired and renders the oil thinner, thereby facilitating an. incorporation of the decolorant with the body of oil. The same results take place at lower temperatures but are ordinarily much more slowly obtained. Working hot, ordinarily the agitation and contact of the decolorant and the oil need be continued only 10 to 30 minutes.

The time of agitation and the amount of decolorant used will of course vary considerably with the nature or grade of the oil to be treated. An advantageous expedient in securing agitation and effective action of the decolorant is to use a certain amount of water with the oil, if it be not already wet; and in practice I often use rather large amounts of water, say a volume equal to that of the oil to be refined. Using a large volume of water with the oil in this way it forms, so to speak, an underlying bed or layer, and on application of heat it boils, effectively agitating the mixture of oil and decolorant overlying it. This method of treatment has the further advantage that the escaping steam or water vapor in passing through the oil acts as an additional purifying agent.

In the process as just described, the entire amount of decolorant to be used was added to the oil at once and agitation of the two together cfi'ected for the desired length of time. But I find it advantageous,'at least in many cases, to add the decolorant in successive small portions. I may, for instance, add the total amount in two to three portions at intervals of, say 5 to 10' minutes. If, for instance 3 per cent of decolorant is to be ued and agitation continued for 15 minutes, I find that I can often secure the best results by adding the decolorant in three portions (each equal to one per cent. of the oil) at intervals of five minutes.

For-example, in brightening and decolorizing a cotton seed oil which may be either a crude oil or a refined oil, I may place a vided with some sort of agitating means,

sucli as perforated steam or air, and heat the whole up to about 100 C.110 C. After the oil has reached this temperature I may add a pound .of the decolorant produced as described for every 100 pounds of oil and agitate energetically for I may then add another pipes for delivering .pound and agitate for five minutes longer. Finally, I may add still another pound of the decolorant and continue the agitation with other oil and then again treating the oil with fresh decolorant. But the simpler method above described is ordinarily sufficient. The filter press cake may be extracted with any of the usual oil solvents, as forinstance, gasolene, to recover adhering oil and then extracted with caustic soda. After extraction with caustic soda it may be washed with water and a little hydrochloric acid and is then ready for reuse. I find that by this method of treating the decolorant cake I can regain the decolorant with practically its original activity.

particular amount of decolorant to be used of course will vary considerably with the quality and nature of the oil under treatment. The darker the oil and the more colloidal matter there is. in it, of course the more decolorant must be used and the longer agitation continued, The method as above described may be applied to the treatment not only of cotton seed oil'but of cocoanut oil, linseed oil, rape seed oil, etc. It may also be applied to the treatment of parafiin, lubricating oil, kerosene, gasolene, etc.

I find that in the described method I can with advantage avail myself of the properties of electrically charged fields in promoting the breakin up of colloid solutions or suspensions. nderthe influence of the electri discharge, the flocculating or partiole-collecting action of the decolorant is .much facilitated. I find that I may, for example, with advantage arrange a pair of plates of some harmless metal, such as aluminum, in the vessel. in which I am treating the oil and keep these plates oppositely charged. Under the influence of the cur-' rent the clarification is much accelerated and the quantity of decolorant necessary for a given oil is reduced. I may connect the vat or tank in which the operation is performed to one pole of a suitable source of electricity of suitable voltage and immerse another pole in the oil. I find that in the case of some oils this action of the electric current is much accelerated by adding a modicum of pulverized insoluble conductive substance, such as aluminum, graphite, etc., to the mix-- ture; As to the reason for'this heightening agitating oil which has already been treated with decolorant which has been used The particular time of treatment and the in effect I am not aware and content my self with notingthe fact;

This utilization of the properties of electrically charged fields in promoting" theaction of my decolorant is not onlyusef'ul in the treatment of oils-in the manner above= described but is also useful in theemployment of such a decolorant-in treatingot-her liquids than ,oil, as for instance glycerin, sugar solutions, glue, etc; And-in the accompanying claims, unless specifically-Sol stated, I do not limit my invention solely'to this application of electricity in connection with-the decolorant in the treatment ofv oils butmean to cover its use .-in connection with the described decolorant in the treatment of a otherliquids which, like the oils, are to be decolorized and heightened in transparency. i r

While, as stated, my invention is applicable for many other materials, -I regard it as particularly applicable to cotton seed oil. Cotton seed oil ordinarily has much color which must be removed in converting it into edible products of high grade; and, it is also usually contamlnated with large.

amounts of very fine particles which the ordinary refining treatments do not wholly remove and which, if they do not actually make the oil. turbid, nevertheless interfere very much with its brilliancy or transparency. Intreating such oils inthe present method I obtain refined oils which are not only transparent and not. turbid but are brilliant in their clearness.

While I regard-the stated decolorant as the best adapted to accomplish my .pur-

poses in the present invention, yet some measure of my advantages may be secured Icy-substituting other, commercial forms of decolorizing carbon while otherwiseoperating-as described. ldut these other formsof carbon do not have as much decolorizing value and lack almost entirely the power of removing the suspended solids, whose removal is necessary for making a brilliant oil.

What I claim is 1. The process of treating oils which comprises mingling such an oil with an open textured granular vegetable ,carbon having open pores representing, approximately the cellular structure of the original vegetable material from which it was made, agitating energetically and separating the oil and decolorant.

prises mingling the oil with a plurality of successively added portions of open textured granular vegetable carbon having open pores representing approximately the cellu-' lar structure of the original vegetable material from which it was made, agitating energetically and separating the oil and decolorant. j

3. The process of treating oils which com-- 120 2. The process of treating oils which comprises mingling such an oil at a temperature of about 100 C, with an open textured granular vegetable carbon having open pores representin approximately the cellular structure 0 the original vegetable material from which it was made, agitating energetically and separating the oil and decolorant.

4. In the brightening and decolorizing of oils, the process which comprises mingling such an oil with an open textured granular Vegetable carbon having open pores representing approximately the cellular structure of the original vegetable material from which it was made agitating energetically and during such agitation maintaining the mixture under the influence of oppositely charged electrical poles, and separating the carbon and decolorant.

5.. In the decolorizing and clarification of liquids with the aid of an open textured granular vegetable carbon having open pores representing approximately the cellular structure of the original vegetable material from which it was made, the process which comprises mixing such a liquid with such a carbon, energetically agitating the two together and during such agitation maintaining the mixture under the influence of oppositely charged electrical poles.

6. In the clarification of oils the process which comprises adding water to such an oil, adding a decolorizing carbon to the oil and heating the assemblage to the boiling point of the water to produce free agitation of the mixture of oil and carbon, and steam out the oil, and separating the oil from the water and the carbon.

7 o In the brightening and decolorizing of oils, the process which comprises mingling such an oil with an open textured granular vegetable carbon havmg open pores representing approximately the cellular structure of the original vegetable material from which it was made, heating the mixture and adding a modicum of a readily conductive pulverulant material, agitating the mixture under the influence of oppositely charged electrical poles, and separating the oil from such mixture.

8. In the brightening-and decolorizing of oils, the process which comprises mingling such an oil with an open textured granular vegetable-carbon having open pores representing approximately the cellular structure of the original vegetable material from which it was made, heating the mixture and adding a modicum of powdered aluminum, agitating the mixture and during such agitation maintaining the mixture under the influence of oppositely charged electrical poles, and separating the oil from the mix-' ture.

9. In the brightening and decolorizing of oils, the process which comprises mingling such an oil with an open textured granular vegetable carbon having open pores representing approximately the cellular structure of the original vegetable material from which it was made, heating the mixture and adding a modicum of a powdered insoluble conductive substance agitating the mixture, and during such agitation maintaining the mixture under the influence of oppositely charged electrical poles, and separating the oil from the mixture.

In testimony whereof, I aflix my signature hereto.

RUSSELL WILLIAM MUMFORD, 

